title: On the topology of chromatin fibres.
abstract: The ability of cells to pack, use and duplicate DNA remains one of the most fascinating questions in biology. To understand DNA organization and dynamics, it is important to consider the physical and topological constraints acting on it. In the eukaryotic cell nucleus, DNA is organized by proteins acting as spools on which DNA can be wrapped. These proteins can subsequently interact and form a structure called the chromatin fibre. Using a simple geometric model, we propose a general method for computing topological properties (twist, writhe and linking number) of the DNA embedded in those fibres. The relevance of the method is reviewed through the analysis of magnetic tweezers single molecule experiments that revealed unexpected properties of the chromatin fibre. Possible biological implications of these results are discussed.
authors.affiliation: Laboratoire de Physique Théorique des la Matière condensée, CNRS UMR 7600, Université Pierre et Marie Curie, Case Courrier 121, 4 place Jussieu 75252, Paris Cedex 05, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Barbi
authors.forename: Julien
authors.initials: J
authors.lastname: Mozziconacci
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Victor
authors.forename: Hua
authors.initials: H
authors.lastname: Wong
authors.forename: Christophe
authors.initials: C
authors.lastname: Lavelle
keywords: DNA; chromatin; topology